Numerous patents have been issued in past years for devices holding more than one padlock, with entry through a gate being possible when a single padlock is opened and removed. The five patents in category A of listed references provide for such action, but the devices involved contain only two padlocks. Category B lists twelve patents describing devices that contain a plurality of separately keyed padlocks, any one of which can be unlocked and removed to allow the opening of a gate.
The seventeen listed patents attest to the fact that continued security may often be required when different individuals are authorized to enter an enclosure at different times. Some might question why a duplicate of the key to a single padlock is not distributed to authorized personnel. One answer to this question came from a canoeing guide in southwest Texas whose residence was located near a river and behind a gate on the only road leading into a fenced ranch area. When asked the purpose of five different locks on a gate-locking device similar to that described by Parker (category B above), his answer was as follows: “If I give out a lot of keys to those who want to have me guide them downriver, then one of the ranch owners who objects to unrecognized intruders will soon find out about it, cut off my lock, and install another so I can't get in myself!” A rule against giving or lending copies of a key to unauthorized personnel is perhaps the main reason for wanting separately keyed locks to be used in opening and closing a gate, but there are other reasons, such as pinpointing responsibility if keys are lost, avoiding the use of expensive electronic systems that may fail to function, or for the manager of a gated area being able to change a specific lock when an individual is no longer authorized to enter, and doing so without the need to issue new keys to all other authorized entrants.
Automatic gate openers that must be actuated to open, preferably from a car window, are currently installed or being considered at the entrance to enclosed areas such as estates, ranches, private clubs, private roadways, sport facilities, home sites, retirement areas, and other locations entered by authorized personnel or their guests. One typical way to actuate a powered gate-opener is to reach from a car window and use a key to operate a switch. After entry, a powered gate-opener functions so as to close the gate automatically. To exit later, a push-button switch may be used, or a car may actuate a buried sensor that serves the purpose of an opening switch. The latter concept is becoming common.
Before listing details and advantages of the invention covered by this patent, it seems appropriate to note some of the disadvantages involved in application of what is described by the seventeen previous patents listed above.
1. The limitation of those in category A, which provide for only two separately keyed padlocks, is obvious.
2. The drawings and descriptions for patents in category B show from four to eight separately keyed padlocks, with implication that this number could be increased. But close analysis of space required between adjacent padlocks indicates that the size of each of the devices would become large and unwieldy if expanded appreciably.
3. None of the listed patents refer to, or show by a drawing, how the locking device covered by the patent could be mounted at some distance from a gate to actuate an automatic gate-opener. This apparently could not be done in a practical way by the devices described.
4. The manual effort and time to find a specific loosely hanging padlock, open and remove it from what may be cramped quarters, manipulate a device so as to withdraw the locking bar involved, open and close a gate, go through steps required to replace the padlock, and later repeat the process, would be frustrating and require added time. Some individuals would tend to pocket the padlock or place it aside, reducing the chore otherwise involved. Security would suffer, particularly if the padlock were lost or stolen.
These disadvantages would either be eliminated or greatly reduced through application of the rotary security system that will next be described.